/***
	Copyright (c) 2008-2011 CommonsWare, LLC
	Licensed under the Apache License, Version 2.0 (the "License"); you may not
	use this file except in compliance with the License. You may obtain	a copy
	of the License at http://www.apache.org/licenses/LICENSE-2.0. Unless required
	by applicable law or agreed to in writing, software distributed under the
	License is distributed on an "AS IS" BASIS,	WITHOUT	WARRANTIES OR CONDITIONS
	OF ANY KIND, either express or implied. See the License for the specific
	language governing permissions and limitations under the License.
	
	From _The Busy Coder's Guide to Advanced Android Development_
		http://commonsware.com/AdvAndroid
*/

package com.commonsware.android.advservice;

import android.app.Service;
import android.content.Intent;
import android.os.IBinder;
import android.util.Log;
import java.util.concurrent.LinkedBlockingQueue;
import bsh.Interpreter;

public class BshService extends Service {
	private final IScript.Stub binder=new IScript.Stub() {
		public void executeScript(String script, IScriptResult cb) {
			executeScriptImpl(script, cb);
		}
	};
	private Interpreter i=new Interpreter();
	private LinkedBlockingQueue<Job> q=new LinkedBlockingQueue<Job>();
	
	@Override
	public void onCreate() {
		super.onCreate();
		
		new Thread(qProcessor).start();
		
		try {
			i.set("context", this);
		}
		catch (bsh.EvalError e) {
			Log.e("BshService", "Error executing script", e);
		}
	}
	
	@Override
	public IBinder onBind(Intent intent) {
		return(binder);
	}
	
	@Override
	public void onDestroy() {
		super.onDestroy();
		
		q.add(new KillJob());
	}
	
	private void executeScriptImpl(String script,
																	IScriptResult cb) {
		q.add(new ExecuteScriptJob(script, cb));		
	}
	
	Runnable qProcessor=new Runnable() {
		public void run() {
			while (true) {
				try {
					Job j=q.take();
					
					if (j.stopThread()) {
						break;
					}
					else {
						j.process();
					}
				}
				catch (InterruptedException e) {
					break;
				}
			}
		}
	};
	
	class Job {
		boolean stopThread() {
			return(false);
		}
		
		void process() {
			// no-op
		}
	}
	
	class KillJob extends Job {
		@Override
		boolean stopThread() {
			return(true);
		}
	}
	
	class ExecuteScriptJob extends Job {
		IScriptResult cb;
		String script;
		
		ExecuteScriptJob(String script, IScriptResult cb) {
			this.script=script;
			this.cb=cb;
		}
		
		void process() {
			try {
				cb.success(i.eval(script).toString());
			}
			catch (Throwable e) {
				Log.e("BshService", "Error executing script", e);
				
				try {
					cb.failure(e.getMessage());
				}
				catch (Throwable t) {
					Log.e("BshService",
								"Error returning exception to client",
								t);
				}
			}
		}
	}
}
